Method of producing a glueless dustless composite flooring material system

ABSTRACT

A method of producing a glueless dustless composite flooring material system providing PVC-based flooring having waterproof layers providing different qualities of hardness, wear-resistance, sound deadening, and decorative patterns, avoiding the use of moisture-susceptible compressed cellulose-based filler, with layers fused together, avoiding the manufacturing complexity and delamination risks of using glue or adhesive, with a quickly-cured, UV-cured top coating providing long-lasting high performance and shortening and simplifying the manufacturing, which can be done in a sheet-form, essentially continuous-run manner, with an ability to quickly and simply change the optional design printing and texturing produced, and having an optional underlayment layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of pending U.S. application Ser. No.17/881,029, filed on Aug. 4, 2022, which is a divisional of U.S.application Ser. No. 17/146,087, filed on Jan. 11, 2021, now U.S. Pat.No. 11,440,232, issued on Sep. 13, 2022, which is a continuation of U.S.application Ser. No. 16/432,106, filed on Jun. 5, 2019, now U.S. Pat.No. 10,889,040, issued on Jan. 12, 2021, which is a continuation-in-partof U.S. application Ser. No. 15/194,891, filed on Jun. 28, 2016, nowU.S. Pat. No. 10,343,381, issued on Jul. 9, 2019, the full disclosuresof which are incorporated by reference herein and priority of which arehereby claimed.

BACKGROUND OF THE INVENTION

This invention provides a method of producing a PVC-based gluelessdustless composite flooring material system that is efficientlymanufactured and yields long-lasting, high-performing flooring.

Existing flooring-material products that use compressed sawdust or dust,as a core material are susceptible to damage and premature failure fromwater or other liquids, especially in damp environments and in uses thatrequire frequent cleaning. The compressed-dust core, however, providesflooring material with certain desirable characteristics, such assound-deadening. Elimination of compressed dust in the flooringcomposition requires a novel way to regain those characteristics throughthe use of different materials or different manufacturing processes.

Existing laminated flooring-material products that use glue or adhesiveto bind the layers are susceptible to delamination and prematurefailure, especially in a damp environment. The handling, the applicationof, and the setting up or curing of adhesives adds complexity to theprocess of manufacturing flooring, making this step a potentialbottleneck, which prevents efficient continuous-run or long runmanufacturing.

Applying a finishing coating to flooring material is a good way toimprove the look and wear-resistance of flooring materials. But wherethe flooring material contains PVC, there are problems and issues inachieving proper adhesion of a finishing coating in the manufacturingprocess, and additional potential problems of premature delaminationafter installation. In order to get good adhesion in manufacturing,coatings requiring long curing times or complex handling are presentlyused. Polyurethane undergoes oxidative curing that is likely to takeeight to ten hours. A two-part epoxy is likely to take at least thirtyminutes to cure, which is still a long time and another potentialbottleneck preventing continuous-run manufacturing. Also, two-part epoxyrequires additional mixing and handling in the manufacturing process.

Surface designs and textures are usually printed on and pressed intoflooring material, frequently imitating wood, stone, or tile. Thepresent methods of applying these decorative patterns and textures aremostly limited to short, frequently repeating patterns that areimpressed by a roller or plate of finite size. Where more than onecolor, tint, tone, or shade is to be applied, problems with registrationfrequently arise. Such limitations work against any ability to switchproduction from one decorative pattern to another. Once the productionof a particular decorative pattern is calibrated and registered, thereis some reluctance to make changes.

Where the manufacturer of flooring material has to address theseproblems, it is likely that either the price will go up or the profitswill go down. If the problems are not addressed, the flooring materialwill likely fail prematurely. A flooring material that is free of anywater-based products, such as inks, or dyes, free of adhesives and freeof compressed cellulose material, such as sawdust or dust, but stillhaving the desired qualities, is thus needed. A manufacturing methodthat is more efficient, more economical, more varied in decorativepatterns, faster, and produces more durable and high-performing flooringmaterial is also presently needed.

U.S. Publication No. 2011/0030300 for a “Floor and Tile with Padding,”published on Feb. 10, 2011 by David C. Liu, discloses a flexible floorboard with a pad attached to the bottom side of the floor board. The padcovers partially the bottom side of the floor board and extends beyondthe floor board. The bottom side of the pad is covered with arestickable glue layer and the floor board has a male lock on one endand a female lock on the other end. A floor board is engaged with anadjacent floor board by pressing down the female lock of the first floorboard onto the male lock of the second floor board. The bottom side ofthe first floor board that is not covered by the pad is placed intocontact with the pad of the second floor board that extends beyond thesecond floor board. The Liu flooring was developed due to the need for ahardwood floor without the problems of both glue-down and floatinginstallation. The hardwood floor was meant to be installed easilywithout messy glue, without delamination, without hollow area, andwithout quick water damage.

U.S. Publication No. 2009/0223162 for a “Connecting System for SurfaceCoverings,” published on Sep. 10, 2009 by Hao A. Chen et al., disclosesa plank that has opposing first and second ends extending along a widthof the plank, opposing first and second longitudinal sides extendingalong a length of the plank, and opposing top and bottom surfaces. Theplank can have a tongue edge at the first end and a groove edge at thesecond end. The tongue edge can be detachably lockable into the grooveedge of an adjacent, identical plank. Surface covering systems having aplurality of the planks connected together are also provided. Inparticular, a preferred embodiment of the floor plank comprises (1) atop surface; (2) a bottom surface; (3) a first longitudinal side; (4) asecond longitudinal side opposing the first longitudinal side; (5) afirst end extending along the width of the floor plank and comprising atongue edge; and (6) a second end opposing the first end, extendingalong the width of the floor plank, and comprising a groove edge. Thetongue edge includes a vertical distal surface, substantially verticalto the top and bottom surfaces; a top planar slanted surface extendingaway from the vertical distal surface toward the top surface; a verticallip extending downwardly from the top surface; a channel disposedsubstantially between the top planar slanted surface and the topsurface, the channel comprising a channel bottom and a channel back, thechannel back extending away from the channel bottom toward the verticallip; a pinnacle rail connecting the top planar slanted surface and thechannel, wherein the channel bottom extends vertically below thepinnacle rail, and the channel back extends laterally further away fromthe vertical distal surface than does the vertical lip; a bottom planarslanted surface extending away from the vertical distal surface towardsthe bottom surface; and a vertical shoulder extending from the bottomplanar slanted surface to the bottom surface.

U.S. Pat. No. 6,558,795 for a “Strippable Coating System,” issued on May6, 2003 to Keith E. Olson et al., provides for a radiation curablecoating that contains an agent that imparts greater strippability to thecured coating. The agent can be included in the coating or in one ormore subsequently-applied maintenance coats. The curable coating may bewaterborne, comprised of inorganic particles, and the agents that impartgreater strippability may enhance adhesion of a radiation curablemaintenance coat to the cured coating. The agent may further comprise achain transfer agent that reduces the molecular weight of the curedcoating, and in a preferred embodiment may contain an alcohol, ester,aldehyde, or mixture thereof.

U.S. Pat. No. 6,730,388 for a “Coating Having Macroscopic Texture andProcess for Making Same,” issued on May 4, 2004 to Richard C. MacQueenet al., provides for, in one embodiment, a coated substrate thatcomprises a substrate, a radiation-cured coating or a thermally-curedcoating on at least a portion of the substrate, wherein the coatingcomprises an inherent macroscopic texture. In another embodiment, theinvention provides for a pre-cured coating mixture comprising aradiation-curable resin and an initiator, or a thermally-curable resinand thermal initiator, wherein the radiation- or thermally-curable resinand the respective initiator form a pre-cured coating mixture capable offorming a macroscopic texture upon application of the mixture on asubstrate. In another embodiment, provided for is a pre-cured coatingmixture comprising a radiation- or thermally-curable resin, aninitiator, and texture-producing particles having an effective size toprovide a macroscopic texture upon application of the mixture on asubstrate. In another embodiment, the invention provides a coatedsubstrate comprising a substrate and a radiation- or thermally-curedcoating on at least a portion of the substrate, wherein the coatingcomprises an inherent macroscopic texture. Additionally, provided for isa process for making a coating on a substrate, comprising the steps ofdistributing a pre-cured coating mixture comprising a radiation-curableresin and an initiator or a thermally-curable resin and thermalinitiator over at least a portion of a substrate to form a pre-curedcoating having a macroscopic texture, and radiation-curing or thermallycuring, respectively, the pre-cured coating to form a radiation-cured orthermally-cured coating having the macroscopic texture.

Chinese Publication No. 204920130 for a “Porcelain Timber Apron Brick,”published on Dec. 30, 2015 by Yang P., discloses a porcelain timberapron brick, including a ceramic tile layer, wood board layer, andwaterproof layer. The wood board layer and waterproof layer are fixedrespectively on both sides of the ceramic tile layer, with the woodboard layer located on the upper surface of the ceramic tile layer. Inthe Yang tile, the thickness of the wood board layer and waterprooflayer, in combination is less than the thickness of the ceramic tilelayer. Being equipped with the wood board layer prevents the bricksurface temperature from being excessively low and improves comfortduring use. The waterproof layer effectively prevents the waterloggingon the ground from entering the ceramic tile layer and wood board layer,granting a waterproof performance of the tile.

Chinese Publication No. 201972361 for a “Wood and Ceramic CompositeFloor Tile,” published on Sep. 14, 2011 by Liang Y., discloses a woodand ceramic composite floor tile comprising a core material, a panel,and a bottom plate, wherein the core material is arranged between thepanel and the bottom plate. The core material is connected with thepanel and bottom plate respectively through an adhesion layer, and isone or more ceramic tiles. Frame bars are also provided and are arrangedat the periphery of the core material. The tile attempts to solveproblems of ceramic tile in that existing wood and ceramic compositefloor tiles are easy to damage and feature high manufacturing costs. Thedisclosed tile provides for a composite floor tile that is difficult todamage, easy to process, convenient to install, and has highnon-deformability features, thereby effectively lowering costs of thetile.

U.S. Pat. No. 8,166,718 for a “Horizontally Engineered Hardwood Floorand Method of Installation,” issued on May 1, 2012 to David C. Liu,provides for a floor board that includes a top decorative layer placed aplurality of strips. The plurality of strips is arranged to have some inX-axis orientation and some in Y-axis orientation. The plurality ofstrips also has characteristics that allow the wood floor board to beinstalled as a tile. Specifically, the Liu patent covers a highperformance engineered wood floor board having a length, comprising (1)a top wood layer with wood grain lined up along the length of the floorboard, the top wood layer having a top surface and a bottom surface; (2)a plurality of supporting strips attached under the top wood layer, afirst subset of the plurality of supporting strips being oriented in afirst direction and a second subset of the plurality of supportingstrips being oriented in a second direction, the first subset of theplurality of supporting strips being separated physically from andwithout being in contact with the second subset of the plurality ofsupporting strips, wherein the top wood layer substantially covers thefirst and second subsets of supporting strips; and (3) an adhesive layerplaced between the top wood layer and the plurality of supportingstrips. The adhesive layer covers the bottom surface of the top woodlayer. Additionally, a first supporting strip in the plurality ofsupport strips has a locking lip, and a second supporting strip in theplurality has a recessed slot, and the locking lip of the firstsupporting strip of the high-performance engineering wood floor board isable to couple to the recessed slot of the second supporting strip ofthe floor board.

International Publication No. WO 2005/116362 for “A Ceramic WoodLaminated Floor,” published on Dec. 8, 2005 by Delong Tao, discloses afloor consisting of a base layer that is made of ceramic tile, and asurface layer that is made of wood or bamboo. Between the surface layerand the base layer, a bonding coat is set. The undersurface of the baselayer is equipped with an elastic pad.

SUMMARY OF THE INVENTION

This invention provides a method of producing a glueless dustlesscomposite flooring material system of PVC-based flooring havingwaterproof layers providing different qualities of hardness, wearresistance, sound deadening, and decorative patterns, with layers fusedtogether without glue or adhesives, with a UV-cured top coating,optional, changeable design printing and texturing, and optionallyhaving an underlayment layer, which can be manufactured in a sheet-form,essentially continuous-run manner, with an ability to quickly and simplychange the optional design printing and texturing produced, yielding along-lasting, high-performing flooring product.

This invention avoids the use of water-permeable compressed cellulosematerial such as sawdust filler, which is susceptible to water damagesuch as swelling and failing. This invention avoids the use of glue oradhesive, which is susceptible to premature delamination failure andwhich increases the costs and complexity of manufacturing. The flooringmaterial provides a floor covering material free of water-basedmaterials, such as water-based inks or dyes. The desirable qualities ofcompressed-dust filler and of glue or adhesive are provided in novelways.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made to the drawings, wherein like parts aredesignated by like numerals, and wherein:

FIG. 1 is a schematic cutaway view of an embodiment of the gluelessdustless composite flooring material system of the invention;

FIG. 2 is schematic exploded view of an embodiment of the gluelessdustless composite flooring material system of the invention;

FIG. 3 is a schematic exploded view of embodiments of the gluelessdustless composite flooring material system of the invention;

FIG. 4 is a schematic cutaway view of another embodiment of the gluelessdustless composite flooring material system of the invention, imitatingterrazzo;

FIG. 5 is a schematic cutaway view of another embodiment of the gluelessdustless composite flooring material system of the invention, imitatingmarble;

FIG. 6 is a schematic cutaway view of an embodiment of the gluelessdustless composite flooring material system of the invention, having asingle-extruded base layer;

FIG. 7 is a schematic cutaway view of an embodiment of the gluelessdustless composite flooring material system of the invention, having adouble-extruded base layer; and

FIG. 8 is a flow chart representation of the method of production of theglueless dustless composite flooring material system of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to all figures generally, embodiments of the glueless dustlesscomposite flooring system 100 and production method 200 are illustrated.

Referring to FIG. 1 and FIG. 2 , the glueless dustless compositeflooring system 100 comprises three waterproof layers 20, 30, 40 ofdifferent materials strongly bonded one to another without the use ofseparate glues or adhesives, and an optional underlayment layer 10. Theoptional underlayment layer 10 can be a natural material such as cork orrubber, or a synthetic material such as either an open-cell or a closedcell plastic foam. Ethylene vinyl acetate (EVA) is a suitable material.The glueless dustless composite flooring system 100 provides awaterproof covering for any type of optional underlayment layer 10 used,allowing the use of water sensitive materials for the underlayment. Theoptional underlayment layer 10 can be omitted, can be affixed to thefinished flooring during manufacture, or can be made available as aseparately packaged item. Depending upon the ability of any particularunderlayment material to withstand the hot-melt overlaying processdisclosed below, the underlayment can be affixed to the rest of theglueless dustless composite flooring system 100 either earlier or laterin the manufacturing process.

The glueless dustless composite flooring system 100 provides awaterproof flooring base layer 20, which is formed by fusion, extrusion,and mold, forming of a blended mixture of PVC resins and other materialsaccording to the glueless dustless composite flooring system method 200illustrated in FIG. 8 and disclosed in more detail below. Optionally,two or more different mixtures of PVC resins and other fusion-compatiblematerials can be co-extruded into the same mold, which will produce afused flooring base layer 20 with different sublayers or strata, such asthe first base extrusion 21 and the second base extrusion 22illustrated. The PVC-resin blend can be adjusted through the use ofdifferent materials and fillers, or different proportions of materialsand fillers, to have different properties when fused and extruded. Ifone PVC-resin blend yields a desired hardness and stability, but isdeficient in sound-deadening or other sponginess qualities, then adifferent PVC-resin blend or a different extrusion technique can beapplied as a co-extrusion in order to provide the otherwise-missingqualities. In a preferred co-extruded embodiment, a stiffer, harderstratum is formed for strength and a dense-foam, springier stratum isformed for cushioning and sound absorption.

The ability to adjust the characteristics of the waterproof flooringbase layer 20, and therefore of the overall finished flooring, byadjustment of one or more PVC-resin blends and one or more extrusionmethods eliminates the need to use compressed dust, which is vulnerableto moisture and is otherwise problematic in some climates and for someuses. For example, the formation of a controlled amount of a dense foamconsistency in the flooring base layer 20, either in that entire layeror stratified within that layer, depending on the concurrent need forstiffness, can duplicate the desirable qualities of a compressed-dustcore, but without the disadvantages of the dust.

In one of the preferred embodiments, the mix of fusion-compatiblematerials included in a suitable flooring base layer 20 is: (a) 50 kgPVC; (b) 100-175 kg 800-1000 mesh calcium carbonate (CaCO3); (c) 3.8-5.0kg calcium/zinc heat stabilizer; (d) 2.5-5.0 kg chlorinated polyethyleneelastomer; (e) 1.0-4.0 kg acrylic polymer modifier; (f) 0.4-0.6 kginternal lubricant; and (g) 0.5-1.5 kg high melting point polymer; and,optionally, (h) 0.2-0.3 kg high density polyethylene oxide.

In preferred embodiments, the PVC mixture comprises, by weight: between20% and 35% polyvinylchloride, between 63% and 73% calcium carbonate,between 2% and 2.5% calcium/zinc heat stabilizer, between 1.6% and 2.5%chlorinated polyethylene elastomer, between 0.6% and 1.7% acrylicpolymer modifier, between 0.2% and 0.25% internal lubricant, between0.32% and 0.62% high melting point polymer, and optionally, between0.06% and 1.22%, and optionally, between 0.1% and 0.12% high densitypolyethylene oxide. This mixture is suitable for either a singlyextruded base layer or for a co-extruded layer or multiple co-extrudedlayers.

The method of producing the waterproof glueless dustless flooringmaterial system provides for the mixing of the materials for theflooring base layer 20 in a suitable large container until the materialsare thoroughly mixed. Then, either in the same large container or in adifferent one, the fusing step provides for the heating of the mixtureof materials while continuing the mixing of the materials. A preferredembodiment of the method heats the mixture to 115-130° C. while stirringat a high speed approaching, but not exceeding, 1600 RPM. After fusionis complete, the fused PVC material is allowed to cool somewhat. The PVCmaterial is destined to be re-heated in the extrusion process, so if thebatch of fused mixture is to be immediately sent to the extruder, thenthe fused mixture needs to be cooled enough to be safely and efficientlyconveyed from the dusty mixing and fusing area to the cleaner environsof the extrusion and molding area. This conveyance or delivery can beeffected by using a large pipe, as is known in the art. Water or anothercoolant can be circulated in a jacket around the container used forfusing in order to carry heat away from the fused PVC mixture, takingcare not to force too rapid of cooling, which might affect the plasticproperties of the flooring base layer 20.

The mixing, fusing, and cooling steps are by nature batch processes.However, by careful adjustment and control of the processes, or bysetting up more than one production line and staggering its operation,an essentially continuous supply of fused PVC material can be producedand supplied to the subsequent operations.

The fused PVC mixture is conveyed to a screw extruder for extrusion toan extrusion mold at an elevated temperature and pressure. A preferredembodiment is extruded using an 80 mm-diameter screw at a speed notexceeding 40 RPM, an extrusion pressure of 20-35 mpa, and a temperatureof 160-186° C. More than one mixture can be co-extruded to the sameextrusion mold for the purpose of forming different strata, as disclosedabove. This extruding and mold-forming process yields a sheet offlooring base layer 20. The sheet can be very long, or essentiallycontinuous. If the mixing-fusing-cooling-delivering steps of the processare properly coordinated so as to provide a continuous supply of fusedPVC material to the screw extruder, then the extruder can supply anessentially continuous sheet of flooring base layer 20 for hot-meltoverlaying of an essentially continuous sheet of flooring face layer 30.

The flooring face layer 30 comprises a decorative face sublayer 31 fusedto a wearing face sublayer 32. The decorative face sublayer 31 can beformed from a PVC decorative film, and will usually be opaque and of acolor acting as a base color or background color for any decorativepattern 33 that is intended to be applied, such as imitations of wood,stone, or tile, or other decorative patterns. The wearing face sublayer32 can be formed from a high molecular wear-resistant PVC polymer film,usually clear or mostly clear, so that the decorative face sublayer 31may be seen. In most embodiments of the glueless dustless compositeflooring system 100, a decorative pattern 33 will be applied to thedecorative face sublayer 31 before it is fused with the wearing facesublayer 32. The decorative pattern 33 is likely to be in imitation oftraditional flooring materials such as wood, stone, or tile. Referringbriefly to FIG. 3 , illustrating schematically that the flooring facelayer 30 might have a decorative pattern in imitation of marble,terrazzo, or wood, different decorative patterns 33 can be used with theglueless dustless composite flooring system 100. The patterns can beapplied with a printing roller or with a digital image-printing device.An advantage of digital printing is that an image with no exactrepetition or a very long period of repetition can be produced, incontrast with the repetition inherent in roller printing. Anotheradvantage of digital printing is that several different colors, shades,or tones can be applied or even blended in place, which is either verycumbersome or is not possible with roller printing in afloor-manufacturing environment.

The PVC decorative film forming the decorative face sublayer 31 can besupplied in large rolls. The strength and wear characteristics of thisPVC decorative film do not significantly influence the strength and wearcharacteristics of the finished flooring, because other elements providesuch strength and wear characteristics. As a practical matter, the PVCdecorative film should be strong enough to avoid tearing during thefloor-manufacturing process.

The use of a high-molecular wear-resistant PVC polymer film for thewearing face sublayer 32 provides a significant portion of the desiredwear resistance of the finished flooring, with the flooring coatinglayer 40 providing the rest. This film can also be supplied in largerolls.

An essentially continuous sheet of flooring face layer 30 can beproduced by using large rolls of the PVC films, or by having anefficient re-loading method.

Although the wearing face sublayer 32 can be fused to the decorativeface sublayer 31 as a separate step in the manufacturing process, beforesubsequently being fused with the flooring base layer 20, a preferredembodiment of the glueless dustless composite flooring system method 200provides for simultaneous fusing of the wearing face sub layer 32, thedecorative face sublayer 31, and the flooring base layer 20 in one pass.This fusion is achieved by hot-melt overlaying, bringing the sublayersand layers into contact with one another in the proper order, andsimultaneously heating and applying compression to the stack to fuse thelayers together without the use of glue or adhesive, and thereforeessentially eliminating potential problems of delamination or otherfailure of the finished flooring. The hot-melt overlaying can beeffected by feeding the wearing face sublayer 32, the decorative facesublayer 31, and the flooring base layer 20 into a set of heatedrollers. Where the wearing face sublayer 32 and the decorative facesublayer 31 are supplied as large rolls of PVC polymer films ofessentially equal width, and the flooring base layer 20 is formed insheets of essentially the same width as the rolls of films, or indivisions of that width allowing side-by-side simultaneous processing ofmultiple sheets, the hot-melt overlaying can be performed in acontinuous or nearly continuous run.

Optionally, a textured, embossed, synchronized embossed, debossed, orsynchronized debossed surface pattern can be applied to the flooringface layer 30 of the fused base and face layers. Such a texture can bean imitative decorative texture complementing or synchronizing with aprinted decorative pattern 33, or can be a texture intended to improvetraction, light reflection, or other qualities of the finished flooring.The textured, embossed, synchronized embossed, debossed, or synchronizeddebossed surface pattern can be applied to the flooring face layer 30 ofthe fused base and face layers either concurrently with the hot-meltoverlaying compression stage or immediately after, while the flooringface layer 30 is still partially melted and pliable. The hot-melt rolleror rollers making contact with the flooring face layer 30 can beconfigured to emboss the texture, although the arrangement would requireeither a small repetitive period of the texture or a large roller. Theembossing can be performed by one or more rollers, plates, or otherdevices, such as rakes pressing into the flooring face layer 30 of thenow-fused base and face layers immediately after the hot-melt overlayingcompression, while the partial assembly is still pliable. Depending onthe amount and nature of the texturing, cylinders of stiff wire could beused as rollers for debossing, perforated cylinders could be used asrollers for embossing, or a rake arrangement, possibly allowing formovement of the tines in order to create variation, could be used.

The hot-melt overlaying fuses the flooring face layer 30 and theflooring base layer 20 together without the use of glue or adhesive. Theface-and-base subassembly emerges from the hot-melt overlaying andoptional texturing at a very high temperature. The face-and-basesubassembly is then conditioned. This conditioning step allows the faceand-base subassembly to cool to the ambient temperature fairly slowlyand evenly, without quenching or other sudden cooling, in order toprevent the development of stress in the sheet. Because theface-and-base subassembly is a thin sheet that is almost completelysurface area, the cooling does not require an inordinate amount of time,and conditioning can be effected on a continuous-run basis by providinga sufficient extra length of conveyor belt to allow for cooling.Optionally, additional conditioning procedures can be performed, such ascorona discharging or flaming in order to prepare the PVC surface forapplication of the flooring coating layer 40. The optional underlayment10 can be added to the subassembly at this point or subsequent pointsafter the hot-melt overlaying and optional texturing have beenperformed.

An essentially continuous sheet of the face-and base subassembly can beproduced by the hot-melt overlaying step if there is a continuous supplyof base-layer and face-layer sheet.

After the face-and-base subassembly has cooled in the conditioning step,the subassembly is then coated on the top or flooring-face-layer 30 sidewith a plastic resin which can be cured under ultraviolet (UV) light,forming a flooring coating layer 40. UV-curing primers and top coatingssuit able for application onto PVC are known in the art. Generally, theUV-curing primer and top coating will be clear, colorless, andtransparent, allowing the decorative pattern 33 to show through.Generally, colorless coatings can be cured more quickly and with lessexposure than colored coatings. UV-curing top coats are available whichprovide a glossy finish or a matte finish, and which have such desirableproperties as scratch resistance. Optionally, a gritty particulatematerial such as aluminum oxide or ceramic powder or other anti-abrasivematerial can be added to the UV-curing plastic resin and incorporatedinto the flooring coating layer 40 to provide additional traction andadditional wear resistance. In a preferred embodiment, the UV primer andthe UV top coats are applied with a series of rollers in long runs or acontinuous run.

There should be an application of UV-curing primer and at least oneapplication of UV-curing top coat, although more than one application ofUV-curing top coat will likely improve the appearance and durability ofthe finished flooring. The curing is effected by exposure to UV lightfrom, for example, Mercury (Hg) lamps or Gallium (Ga) lamps. UV curingis effected very quickly, in only a few seconds, and can be accomplishedin the time that a work piece travels on a conveyer belt passing under abank of UV lights. In contrast, oxidative curing of polyurethane islikely to take eight to ten hours, and curing of a two-part epoxy islikely to take at least thirty minutes or more.

The use of UV-curing plastic resins in the flooring coating layer 40 ofthe glueless dustless composite flooring system method 200 eliminates apotential bottleneck in the manufacturing process, which enablesproduction of an essentially continuous sheet of fully assembled, fused,deco rated, coated, and cured flooring material. The coating and UVcuring of the fused base-and-face subassembly yields afinished-large-sheet assembly of a composite flooring material thatincorporates the flooring base layer 20, the flooring face layer 30, andthe flooring coating layer 40, with an optional underlayment layer 10.This finished-large-sheet assembly is intended to be divided intosegments of desired size and configuration, such as a tile or a plank,which can be easily handled during installation, or a large rolledsheet.

The final steps in the glueless dustless composite flooring systemmethod 200 are profile processing, in which the large sheet of finishedflooring material is cut to the desired size and has the appropriatenotches, grooves, tabs, or other installation-related components formed.Optionally, bevels can be processed on two sides or four sides ofprofiled flooring material, painted with colors, sometimes to imitatedesigns on wood, tiles, textile or marble, such as grey color on bevelsto simulate grout lines between tiles and black or dark colors tosimulate French bleed on wood. From a profile view, the bevels could bein different shapes, like straight lines forming angles, or square, orrounded arcs. Then inspect and pack the finished flooring material fortransport and sale.

Referring to FIG. 8 , a flowchart representation of the gluelessdustless composite flooring system production method 200, the flooringbase layer 20 is formed from PVC and other raw materials by the mixing,fusing, cooling, delivering, extruding, mold-forming, andconditioning-cooling, yielding a sheet-form supply of flooring baselayer 20 that can be essentially continuous. The flooring face layer 30is separately, and potentially simultaneously, formed by providing PVCdecoration film, optionally printing a decorative pattern 33 upon it,and then adding PVC wear resistant film, yielding a sheet-form supply offlooring face layer 30 that can also be essentially continuous. Then thesheets of flooring base layer 20 and flooring face layer 30 are broughtinto proximity in the appropriate orientation and fused together,without glue or adhesives, by hot-melt over laying, optionally followedby texturing, yielding a sheet form supply of base-and-face subassemblythat can also be essentially continuous. Then a conditioning step allowsthe hot-melted base-and-face subassembly to cool, and optionallyprovides other conditioning procedures. Then a coating of UV-curingplastic resin is applied as a primer layer and at least one top coatlayer. After each application of UV-curing plastic resin, the sheet ofcoated flooring material is subjected to UV curing by exposure to UVlight, effecting a very rapid curing. The conditioning, coating, and UVcuring processes can be performed on an essentially continuous,sheet-form supply of base-and-face subassembly, and yields a sheet-formsupply of finished, fused, coated, and cured flooring material that canalso be essentially continuous. Then the sheet of finished flooring iscut to size and has any notches, grooves, or tabs for installationpurposes formed in the profile processing step. Inspecting and packingthe profiled flooring-material pieces are the finals steps.

The glueless dustless composite flooring system method 200 provides anability to manufacture flooring on a continuous-run assembly-lineconveyor-belt basis. It also provides an ability to efficiently changeproduction from one color or design pattern to another. It yields aflooring material product that contains no dust and no glue, yetpossesses the desirable qualities associated with dust and glue, whichare achieved by other, novel means.

It is envisioned that digital printing can be applied to the baseflooring layer 20. In such case, before application, hydro UV primer isapplied for good adhesion properties, and then UV putty applied for asmooth base. Next, a UV sealer is applied for a standard white base forprinting on PVC. With digital printing especially, the design optionsare almost endless. Before printing, texture can be achieved by usingdifferent rollers to achieve the desired textured look, such as forinstance, smooth, hand scraped, embossed in registered, tick marked, sawmarked, BP, and wood grain. After printing, anti-abrasive sealer,sanding sealer, structure coating, and anti-scratch top coating will beapplied, which provides anti-scratch and anti-abrasive wear layer. Inthis case, there may not be a need for the flooring face layer 30, whichhas a PVC decorative film and a high molecular wear-resistant PVCpolymer film.

Many other changes and modifications can be made in the presentinvention without departing from the spirit thereof. We therefore praythat our rights to the present invention be limited only by the scope ofthe appended claims.

What is claimed is: 1-22. (canceled)
 23. Composite flooring materialsegments, each composite flooring material segment comprising: (i) aflooring base layer comprising a mixture of PVC resin and calciumcarbonate, wherein said mixture is free of glue, and wherein saidflooring base layer is a resultant of extrusion of the mixture atelevated temperature and pressure, mold-forming the extruded mixtureinto said flooring base layer, and cooling said flooring base layer;(ii) a waterproof flooring face layer comprising a decorative facesublayer and a wearing face sublayer fused onto a top face of saiddecorative face sublayer, where said flooring face layer is fused onto atop face of said flooring base layer by hot-melt overlaying of saidlayers; and (iii) a cured waterproof flooring coating layer, applied ontop of said flooring face layer, wherein said flooring coating layer isthe resultant of coating said flooring face layer with a UV-curingplastic resin and UV curing said coating of UV-curing plastic resin byexposure to UV light.
 24. (canceled)
 25. The composite flooring materialsegments of claim 23, where said flooring base layer is free ofcompressed cellulose material.
 26. The composite flooring materialsegments of claim 23, where said flooring base layer is a waterprooflayer.
 27. The composite flooring material segments of claim 23, wheresaid mixture comprises, by weight, between 20% and 35%polyvinylchloride, and between 63% and 73% calcium carbonate.
 28. Thecomposite flooring material segments of claim 23, where said mixturecomprises, by weight, between 2% and 2.5% calcium/zinc heat stabilizer,between 1.6% and 2.5% chlorinated polyethylene elastomer, between 0.6%and 1.7% acrylic polymer modifier, between 0.2% and 0.25% internallubricant, and between 0.32% and 0.62% high melting point polymer. 29.(canceled)
 30. The composite flooring material segments of claim 23,where said decorative face sublayer is a PVC decorative polymer film.31. The composite flooring material segments of claim 30, where a designis printed onto said PVC decorative polymer film.
 32. The compositeflooring material segments of claim 30, where said PVC decorativepolymer film further comprises a colored film.
 33. The compositeflooring material segments of claim 23, where said wearing face sublayeris a PVC wear-resistant polymer film.
 34. The composite flooringmaterial segments of claim 33, where said PVC wear-resistant polymerfilm is transparent.
 35. The composite flooring material segments ofclaim 23, where said flooring coating layer is transparent.
 36. Thecomposite flooring material segments of claim 23, where said flooringcoating layer further comprises a gritty particulate material.
 37. Thecomposite flooring material segments of claim 23, where said flooringcoating layer further comprises aluminum oxide.